Field of the Invention
The invention relates to the field of conveying devices with a braking device. Such a conveying device includes a circulatorily led, extensively extended conveying element which forms a conveying section with a conveying surface and a return section. It also includes a front head-end region, in which the conveying element is deflected from the conveying section into the return section in the movement direction of the conveying element, as well as a braking device which is designed for exerting a braking effect upon the driven conveying element.
Description of Related Art
The braking devices in the conveying devices are used in order to brake the conveying element and in particular to move it in a controlled manner by way of the braking. Braking devices which interact with a drive are often used, and this permits a high degree of control of the movements of the conveying element. Braking devices amongst other things can be used in order to subject the conveying element or at least a section of the conveying element which is located downstream of the brake in the movement direction of the conveying element, to tension in a targeted manner. The conveying element and, in particular the conveying surface, can be kept taught and/or in the desired shape (e.g., plane) at the corresponding locations by way of tension, at least on the section of the conveying element.
Conveying devices with a circulating, extensively extended conveying element such as a conveying belt or mat chain are known from the state of the art. The conveying elements as a rule are driven via a deflection shaft at one or two deflection locations. Known conveying devices have stationary braking devices with a braking element, which is co-moved with the conveying element. The movement of the conveying element is thereby transmitted onto the braking element and is weakened, thus braked, in the braking device. Thereby, the braking element can be designed as an element engaging into the conveying element, such as a cog, or as a non-engaging element such as a roller.
In a known embodiment, the conveying element is tensioned and deflected between a first braked deflection shaft (thus a co-moved braking element rotating about a stationary axis) and a second non-braked deflection shaft. Thereby, the first braked deflection shaft in a simple embodiment manner can merely be braked by a resistance from its rotary mounting. The braking effect of the first braked deflection roller can increase due to the tensioning between the first and the second deflection shaft.
The mentioned conveying devices are particularly applied as worker-rider belts. Worker-rider belts are designed in order to carry persons working along a production line or on a conveyor belt, and to convey them at least temporarily or continuously in the production direction, so that the persons working in the production line or on the conveyor belt are moved along with the manufactured goods conveyed through the production line or on the conveyor belt. Worker-rider belts are particularly characterised by a low construction height.
Thus, DE 10 2006 010 974 describes a worker-rider belt with a conveying belt as well as an essentially horizontal guide frame with two lateral sidewalls, which extend horizontally in the longitudinal direction of the conveying belt. A deflection roller, which is driven by a drive, is rotatably mounted at the ends of the worker-rider belt in each case. The drive is arranged between the two sidewalls. The conveying belt is tensioned between the two deflection rollers by way of adjustable tensioning devices.
The known braking devices with co-moved braking elements have the disadvantage that their design is complicated. Thus, these braking devices are expensive and complicated in manufacture. An increased probability of failure is also given due to a high number of individual parts. The maintenance and overhaul of such conveying devices accordingly demand much effort and are time-consuming and costly.
In the variant with the tensioned conveying element, the conveying device has the disadvantage that the conveying element is under constant tension, even if the conveying device does not convey anything and even if it is at standstill. The conveying element can become stretched in the course of time due to a continuous tension. This, in turn, can necessitate a (repeated) post-tensioning of the conveying element. Such a tension can load and wear the conveying element.